/*
 * Copyright (c) 2016-2017, ARM Limited and Contributors. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#include <arch.h>
#include <arch_helpers.h>
#include <assert.h>
#include <cassert.h>
#include <common_def.h>
#include <debug.h>
#include <platform_def.h>
#include <string.h>
#include <types.h>
#include <utils.h>
#include <xlat_tables.h>
#include "xlat_tables_private.h"

#if LOG_LEVEL >= LOG_LEVEL_VERBOSE
#define LVL0_SPACER ""
#define LVL1_SPACER "  "
#define LVL2_SPACER "    "
#define LVL3_SPACER "      "
#define get_level_spacer(level)        \
            (((level) == U(0)) ? LVL0_SPACER : \
            (((level) == U(1)) ? LVL1_SPACER : \
            (((level) == U(2)) ? LVL2_SPACER : LVL3_SPACER)))
#define debug_print(...) tf_printf(__VA_ARGS__)
#else
#define debug_print(...) ((void)0)
#endif

#define UNSET_DESC    ~0ull

static uint64_t xlat_tables[MAX_XLAT_TABLES][XLAT_TABLE_ENTRIES]
            __aligned(XLAT_TABLE_SIZE) __section("xlat_table");

static unsigned int next_xlat;
static unsigned long long xlat_max_pa;
static uintptr_t xlat_max_va;

static uint64_t execute_never_mask;

/*
 * Array of all memory regions stored in order of ascending base address.
 * The list is terminated by the first entry with size == 0.
 */
static mmap_region_t mmap[MAX_MMAP_REGIONS + 1];


void print_mmap(void)
{
#if LOG_LEVEL >= LOG_LEVEL_VERBOSE
    debug_print("mmap:\n");
    mmap_region_t *mm = mmap;
    while (mm->size) {
        debug_print(" VA:%p  PA:0x%llx  size:0x%zx  attr:0x%x\n",
                (void *)mm->base_va, mm->base_pa,
                mm->size, mm->attr);
        ++mm;
    };
    debug_print("\n");
#endif
}

void mmap_add_region(unsigned long long base_pa, uintptr_t base_va,
            size_t size, mmap_attr_t attr)
{
    mmap_region_t *mm = mmap;
    mmap_region_t *mm_last = mm + ARRAY_SIZE(mmap) - 1;
    unsigned long long end_pa = base_pa + size - 1;
    uintptr_t end_va = base_va + size - 1;

    assert(IS_PAGE_ALIGNED(base_pa));
    assert(IS_PAGE_ALIGNED(base_va));
    assert(IS_PAGE_ALIGNED(size));

    if (!size)
        return;

    assert(base_pa < end_pa); /* Check for overflows */
    assert(base_va < end_va);

    assert((base_va + (uintptr_t)size - (uintptr_t)1) <=
                    (PLAT_VIRT_ADDR_SPACE_SIZE - 1));
    assert((base_pa + (unsigned long long)size - 1ULL) <=
                    (PLAT_PHY_ADDR_SPACE_SIZE - 1));

#if ENABLE_ASSERTIONS

    /* Check for PAs and VAs overlaps with all other regions */
    for (mm = mmap; mm->size; ++mm) {

        uintptr_t mm_end_va = mm->base_va + mm->size - 1;

        /*
         * Check if one of the regions is completely inside the other
         * one.
         */
        int fully_overlapped_va =
            ((base_va >= mm->base_va) && (end_va <= mm_end_va)) ||
            ((mm->base_va >= base_va) && (mm_end_va <= end_va));

        /*
         * Full VA overlaps are only allowed if both regions are
         * identity mapped (zero offset) or have the same VA to PA
         * offset. Also, make sure that it's not the exact same area.
         */
        if (fully_overlapped_va) {
            assert((mm->base_va - mm->base_pa) ==
                   (base_va - base_pa));
            assert((base_va != mm->base_va) || (size != mm->size));
        } else {
            /*
             * If the regions do not have fully overlapping VAs,
             * then they must have fully separated VAs and PAs.
             * Partial overlaps are not allowed
             */

            unsigned long long mm_end_pa =
                             mm->base_pa + mm->size - 1;

            int separated_pa =
                (end_pa < mm->base_pa) || (base_pa > mm_end_pa);
            int separated_va =
                (end_va < mm->base_va) || (base_va > mm_end_va);

            assert(separated_va && separated_pa);
        }
    }

    mm = mmap; /* Restore pointer to the start of the array */

#endif /* ENABLE_ASSERTIONS */

    /* Find correct place in mmap to insert new region */
    while (mm->base_va < base_va && mm->size)
        ++mm;

    /*
     * If a section is contained inside another one with the same base
     * address, it must be placed after the one it is contained in:
     *
     * 1st |-----------------------|
     * 2nd |------------|
     * 3rd |------|
     *
     * This is required for mmap_region_attr() to get the attributes of the
     * small region correctly.
     */
    while ((mm->base_va == base_va) && (mm->size > size))
        ++mm;

    /* Make room for new region by moving other regions up by one place */
    memmove(mm + 1, mm, (uintptr_t)mm_last - (uintptr_t)mm);

    /* Check we haven't lost the empty sentinal from the end of the array */
    assert(mm_last->size == 0);

    mm->base_pa = base_pa;
    mm->base_va = base_va;
    mm->size = size;
    mm->attr = attr;

    if (end_pa > xlat_max_pa)
        xlat_max_pa = end_pa;
    if (end_va > xlat_max_va)
        xlat_max_va = end_va;
}

void mmap_add(const mmap_region_t *mm)
{
    while (mm->size) {
        mmap_add_region(mm->base_pa, mm->base_va, mm->size, mm->attr);
        ++mm;
    }
}

static uint64_t mmap_desc(mmap_attr_t attr, unsigned long long addr_pa,
                            unsigned int level)
{
    uint64_t desc;
    int mem_type;

    /* Make sure that the granularity is fine enough to map this address. */
    assert((addr_pa & XLAT_BLOCK_MASK(level)) == 0);

    desc = addr_pa;
    /*
     * There are different translation table descriptors for level 3 and the
     * rest.
     */
    desc |= (level == XLAT_TABLE_LEVEL_MAX) ? PAGE_DESC : BLOCK_DESC;
    desc |= (attr & MT_NS) ? LOWER_ATTRS(NS) : 0;
    desc |= (attr & MT_RW) ? LOWER_ATTRS(AP_RW) : LOWER_ATTRS(AP_RO);
    desc |= LOWER_ATTRS(ACCESS_FLAG);

    /*
     * Deduce shareability domain and executability of the memory region
     * from the memory type.
     *
     * Data accesses to device memory and non-cacheable normal memory are
     * coherent for all observers in the system, and correspondingly are
     * always treated as being Outer Shareable. Therefore, for these 2 types
     * of memory, it is not strictly needed to set the shareability field
     * in the translation tables.
     */
    mem_type = MT_TYPE(attr);
    if (mem_type == MT_DEVICE) {
        desc |= LOWER_ATTRS(ATTR_DEVICE_INDEX | OSH);
        /*
         * Always map device memory as execute-never.
         * This is to avoid the possibility of a speculative instruction
         * fetch, which could be an issue if this memory region
         * corresponds to a read-sensitive peripheral.
         */
        desc |= execute_never_mask;

    } else { /* Normal memory */
        /*
         * Always map read-write normal memory as execute-never.
         * (Trusted Firmware doesn't self-modify its code, therefore
         * R/W memory is reserved for data storage, which must not be
         * executable.)
         * Note that setting the XN bit here is for consistency only.
         * The function that enables the MMU sets the SCTLR_ELx.WXN bit,
         * which makes any writable memory region to be treated as
         * execute-never, regardless of the value of the XN bit in the
         * translation table.
         *
         * For read-only memory, rely on the MT_EXECUTE/MT_EXECUTE_NEVER
         * attribute to figure out the value of the XN bit.
         */
        if ((attr & MT_RW) || (attr & MT_EXECUTE_NEVER)) {
            desc |= execute_never_mask;
        }

        if (mem_type == MT_MEMORY) {
            desc |= LOWER_ATTRS(ATTR_IWBWA_OWBWA_NTR_INDEX | ISH);
        } else {
            assert(mem_type == MT_NON_CACHEABLE);
            desc |= LOWER_ATTRS(ATTR_NON_CACHEABLE_INDEX | OSH);
        }
    }

    debug_print((mem_type == MT_MEMORY) ? "MEM" :
        ((mem_type == MT_NON_CACHEABLE) ? "NC" : "DEV"));
    debug_print(attr & MT_RW ? "-RW" : "-RO");
    debug_print(attr & MT_NS ? "-NS" : "-S");
    debug_print(attr & MT_EXECUTE_NEVER ? "-XN" : "-EXEC");
    return desc;
}

/*
 * Look for the innermost region that contains the area at `base_va` with size
 * `size`. Populate *attr with the attributes of this region.
 *
 * On success, this function returns 0.
 * If there are partial overlaps (meaning that a smaller size is needed) or if
 * the region can't be found in the given area, it returns -1. In this case the
 * value pointed by attr should be ignored by the caller.
 */
static int mmap_region_attr(mmap_region_t *mm, uintptr_t base_va,
                    size_t size, mmap_attr_t *attr)
{
    /* Don't assume that the area is contained in the first region */
    int ret = -1;

    /*
     * Get attributes from last (innermost) region that contains the
     * requested area. Don't stop as soon as one region doesn't contain it
     * because there may be other internal regions that contain this area:
     *
     * |-----------------------------1-----------------------------|
     * |----2----|     |-------3-------|    |----5----|
     *                   |--4--|
     *
     *                   |---| <- Area we want the attributes of.
     *
     * In this example, the area is contained in regions 1, 3 and 4 but not
     * in region 2. The loop shouldn't stop at region 2 as inner regions
     * have priority over outer regions, it should stop at region 5.
     */
    for (;; ++mm) {

        if (!mm->size)
            return ret; /* Reached end of list */

        if (mm->base_va > base_va + size - 1)
            return ret; /* Next region is after area so end */

        if (mm->base_va + mm->size - 1 < base_va)
            continue; /* Next region has already been overtaken */

        if (!ret && mm->attr == *attr)
            continue; /* Region doesn't override attribs so skip */

        if (mm->base_va > base_va ||
            mm->base_va + mm->size - 1 < base_va + size - 1)
            return -1; /* Region doesn't fully cover our area */

        *attr = mm->attr;
        ret = 0;
    }
    return ret;
}

static mmap_region_t *init_xlation_table_inner(mmap_region_t *mm,
                    uintptr_t base_va,
                    uint64_t *table,
                    unsigned int level)
{
    assert(level >= XLAT_TABLE_LEVEL_MIN && level <= XLAT_TABLE_LEVEL_MAX);

    unsigned int level_size_shift =
               L0_XLAT_ADDRESS_SHIFT - level * XLAT_TABLE_ENTRIES_SHIFT;
    u_register_t level_size = (u_register_t)1 << level_size_shift;
    u_register_t level_index_mask =
        ((u_register_t)XLAT_TABLE_ENTRIES_MASK) << level_size_shift;

    debug_print("New xlat table:\n");

    do  {
        uint64_t desc = UNSET_DESC;

        if (!mm->size) {
            /* Done mapping regions; finish zeroing the table */
            desc = INVALID_DESC;
        } else if (mm->base_va + mm->size - 1 < base_va) {
            /* This area is after the region so get next region */
            ++mm;
            continue;
        }

        debug_print("%s VA:%p size:0x%llx ", get_level_spacer(level),
            (void *)base_va, (unsigned long long)level_size);

        if (mm->base_va > base_va + level_size - 1) {
            /* Next region is after this area. Nothing to map yet */
            desc = INVALID_DESC;
        /* Make sure that the current level allows block descriptors */
        } else if (level >= XLAT_BLOCK_LEVEL_MIN) {
            /*
             * Try to get attributes of this area. It will fail if
             * there are partially overlapping regions. On success,
             * it will return the innermost region's attributes.
             */
            mmap_attr_t attr;
            int r = mmap_region_attr(mm, base_va, level_size, &attr);

            if (!r) {
                desc = mmap_desc(attr,
                    base_va - mm->base_va + mm->base_pa,
                    level);
            }
        }

        if (desc == UNSET_DESC) {
            /* Area not covered by a region so need finer table */
            uint64_t *new_table = xlat_tables[next_xlat++];
            assert(next_xlat <= MAX_XLAT_TABLES);
            desc = TABLE_DESC | (uintptr_t)new_table;

            /* Recurse to fill in new table */
            mm = init_xlation_table_inner(mm, base_va,
                        new_table, level+1);
        }

        debug_print("\n");

        *table++ = desc;
        base_va += level_size;
    } while ((base_va & level_index_mask) &&
         (base_va - 1 < PLAT_VIRT_ADDR_SPACE_SIZE - 1));

    return mm;
}

void init_xlation_table(uintptr_t base_va, uint64_t *table,
            unsigned int level, uintptr_t *max_va,
            unsigned long long *max_pa)
{
    execute_never_mask = xlat_arch_get_xn_desc(xlat_arch_current_el());
    init_xlation_table_inner(mmap, base_va, table, level);
    *max_va = xlat_max_va;
    *max_pa = xlat_max_pa;
}
